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Dj, ASE Certified Technician
Category: Car
Satisfied Customers: 1909
Experience:  ASE Certified Master Technician. 30+ years in the car repair business.
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1981 Porsche 911 Targa: idles

Resolved Question:

Hi there, I recently bought a 1981 Porsche 911 Targa. The car is in fantastic physical shape but there are some mechanical issues. The car has very slugglish acceleration, the engine noise is quite loud (valve issue?) and it idles quite high (1100 to 1300). Also when I shift the car into differnet gears, it grinding gears as well, especially from 2nd to 3rd... I had the car looked at by an expert and he thinks the shifting problems are fixable but he said the engine is very badly tuned and might require some serious work. I am curious what your guys think might be wrong with the engine. Have any of you guys worked on old Porsches before?
Submitted: 6 years ago.
Category: Car
Expert:  Dj replied 6 years ago.



A sluggish Porsche, it can't be!


Start with the basics. The first thing is to check the compression. See if you have a solid engine.


The noise could be a number of things, but the compression test may help to determine what is causing it. The noise and sluggishness might be because of the cam timing off.


Find a good tech. This car is a work of art and mechanical perfection. It needs the right kind of person to work on it. A Porsche club in your area will provide the names of the best techs for this car.


Thank you in advance for accepting my answer. If you need more help, just ask. If you feel that my response isn't helpful, just let me know and I will release your question back into the list.







Customer: replied 6 years ago.
Hi DJ, I certainly agree that the car is a work of art! So if I understand this correctly, if the car passes the compression test, it does not need an engine rebuild? But it could still need serious work?
Expert:  Dj replied 6 years ago.



It might still need an engine overhaul. But you have to start someplace.


If for example, an exhaust valve was burnt in number 5 cylinder, and the previous owner drove the car for a long time, it will eventually destroy the rod bearing. But the compression test is the best place to start. If all the cylinders have low compression, it could have jumped time (cam timing) causing the lack of power and the noise.


If you do a compression test and everything is fine, then something else is causing the lack of power and there may be no deep engine problems. When the compression test is done, if a cylinder is low, a compression leak down test can be performed. If you find that you have 35% leakdown past the piston, then it's time for a rebuild.


There are a lot of different that could be wrong, but the logical place to start is always a compression test.







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